Retreaded tires are typically prepared, for example, by applying a pre-cured rubber tread to a circumferential uncured rubber layer, sometimes referred to as a “cushion layer,” which overlays a buffed tire rubber carcass from which the original rubber tread has been removed by abrading it away, to form an assembly thereof and the assembly cured at an elevated temperature to form a cured retreaded rubber tire. Such tire retreading process is well known to those having skill in such art.
It is desirable for a cushion layer compound to have a short cure time and a long scorch time. Conventionally, productive cushion layer compounds, i.e. compounds that are capable of curing, are made in a Banbury mixer that generates heat in the compound during mixing. The compounds are then stored and subjected to further heat history during shaping of the compound by extrusion or calendering. The extruded or calendered compound may be stored prior to application of the cushion layer to the tire to be retreaded. During the mixing, shaping and storing the cushion layer compound may experience some reaction of the curatives, leading to a shorter shelf life for the compound.
It would therefore be advantageous to have a cushion layer compound capable of maintaining a longer shelf life.